1. Field of the Invention
The present invention relates to novel water-absorbing acrylic fibers, and more specifically relates to novel water-absorbing acrylic fibers compounded of a particular water-absorbing resin and provided with excellent practical properties such as dyeability, spinnability, strength and elongation.
2. Description of the Prior Art
Since acrylic fibers, like other synthetic fibers such as polyamide, polyester, etc. fibers, are lacking in water- and moisture-absorbing abilities, when used as material for underwear, sheeting, sportswear, summer wear, etc. it has been conventional practice in most cases to use them as mixed spun fabrics with cotton, rayon, etc. so that they can give a comfortable wearing feel.
Numerous trials have been made to imrove the water- and moisture-absorbing abilities of acrylic fibers, but to date none have been proposed having satisfactory properties.
For example, when producing acrylic fibers composed of a single component by wet-spinning, if the porous structure of the swollen gel filaments is fixed, acrylic fibers showing a water-absorbing ability can be obtained, but they involve intrinsic disadvantages that the micropores obtained by this method are unstable and will readily disappear in the subsequent drying step or by ironing, resulting in a lowered water-absorbing ability, extremely high absorption of spinning oil, and poor color fastness.
Many proposals have been made on methods of producing micropores in the filaments by spinning a spinning solution to which a specified inorganic or organic substance has been added, and thereafter removing the added substance. However, such methods will pose essential problems including pollution of solvent by said substance or aggravation of working environment, complication of the production process such as the recovery of said substance, and therefore such methods cannot be evaluated as industrially advantageous methods.
Several techniques have been also proposed in which water- and moisture-absorbing abilities are given to acrylic fibers by partially hydrolyzing the fibers. However, such fibers having a large amount of carboxyl group introduced to the fiber surface will show a remarkable decrease in the physical properties and color fasteness, and also will not be able to avoid a sticky feel when they have absorbed water. Therefore such methods are not satisfactory means in practical use.